I have a 1950 that runs great at 74,000 miles. It has burned some oil since we bought it, but it has a blow-by problem that has worsened. I am interested in adding a PCV valve to get rid of the fumes coming out of the road tube. These fumes have reached the attention-getting stage! I found a previous post on a PCV setup, and I have read David Pollock's article in the May-June 96 Plymouth Bulletin. But I do not know what to get for the "Army/industrial fitting" he talks about, to replace the road tube. I need to be able to order components that are readily available. Thanks to all.
Not sure if this will work but I was told that using synthetic oil will stop the blow by smoke the oil will burn it is just not visible.
I have not tested this theory but it may be worth the few extra dollars for the experiment before you do all the extra work.
PCV systems are designed for the blow by expected from an engine in reasonable shape. I suspect that if you are smoking enough to be a problem then a PCV system properly sized for your engine will be inadequate.
That said, if you don't want to order a kit from Vintage Power Wagons there was a "how to make" diagram posted at www.p15-d24.com a while back. Basically it was a short plumbing nipple and cap with a hole drilled in the end it made a cap to cover the port where the draft tube bolts on. Then a hole was drilled in the side of the cap assembly to take a fitting for a tube/hose that goes to a PCV valve for a modern car of about the same displacement. Then another hose from the PCV valve to a convenient port on the intake manifold.
It is easy enough to make an adaptor for the crankcase vent port. PCV is a kind of win win solution but blowby in excess is usually a sign that the upper compression rings are worn or broken.
Broken rings will chew up the pistons pretty quickly and while they rarely result in a complete breakdown, nothing quite compares whit the noise that results when a piece of ring gets above the piston.
Hastings Piston Rings make a "GL" spacer which can be installed in the top groove and will restore a piston which has run with broken rings.
At 75000 miles, most Plymouth sixes were ready for new rings and maybe even a rebore.
You could indeed make up a pcv system for a Plymouth engine using military Dodge parts. The parts from the 230 in the M37 3/4 ton truck would be the correct ones to use.
Understand this, tho.....those parts were fitted to the M37, as were similar parts to the engines of all the M series military vehicles, as part of a 'sealed engine' system, so that the vehicle could literally be run under water, to the height of the driver's nostrils (extension pipes were added to the air intake and exhaust)
You could also, if you wished, fit the military governor type carbie, and the waterproof 'igniter' which fits in place of the distributor and has the coil inbuilt....but you have to change to 24volt electricals to use the igniter system.
None of that is practical for an ordinary road-going Plymouth, as you can well imagine.
Adding a pcv system won't fix your actual problem, which is likely to be a cracked piston, broken rings, or simply extreme wear. It will foul your spark plugs rather quickly, tho.
There's nothing for it but to have the head and oil pan off the engine, have the piston/rod assemblies out, and see just what your problem is.
If your engine has significantly worn bores, as well as worn or broken rings, badly worn ring grooves, etc., you can get by for quite a while by de-glazing the worn bores, replacing the pistons if necessary, or alternatively repairing worn pistons with 'groove insert shims' and 'knurlising' the piston skirts, fitting new rings (the Grant make of cast iron rings, if you can get them), fitting new little-end bushes to the rods, as those wear badly, and, of course, new rod insert bearings.
This level of 'repair', along with regrinding the valves and valve seats, was the famous.....or infamous.....'in-chassis minor overhaul'
As a practical matter, it was an economical way to get few more years use out of the engine before it had to come out for a proper rebuild.
If you have broken rings, and the bad rings have put deep grooves in the bores, well, then there's nothing for it but a proper rebuild.....or find a usable engine for now, and just fit another engine.
cheers
Carla
I heartly agree. Plymouth engines at 70,000 miles need a new set of rings,guides,valves etc. You may get away without a rebore which means you can do the work at your speed in your garage. Sometimes just installing a new set of rings on the original pistons makes a world of difference. If you just drive locally ,and maybe 500 miles each summer, this may be all you have to do. Installing a PCV will just mask the problem of a tired engine.